docs: def cylrec(r, lon, z):
      """
      Convert from cylindrical to rectangular coordinates.
  
      http://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/cspice/cylrec_c.html
  
      :param r: Distance of a point from z axis.
      :type r: float
      :param lon: Angle (radians) of a point from xZ plane.
      :type lon: float
      :param z: Height of a point above xY plane.
      :type z: float
      :return: Rectangular coordinates of the point.
      :rtype: 3-Element Array of floats
      """
      r = ctypes.c_double(r)
      lon = ctypes.c_double(lon)
      z = ctypes.c_double(z)
      rectan = stypes.emptyDoubleVector(3)
      libspice.cylrec_c(r, lon, z, rectan)
      return stypes.cVectorToPython(rectan)